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Synthesis and physico‐chemical properties of nitrocaffeic acids
Author(s) -
Grenier J. L.,
Cotelle N.,
Catteau J. P.,
Cotelle P.
Publication year - 2000
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/1099-1395(200009)13:9<511::aid-poc283>3.0.co;2-8
Subject(s) - chemistry , caffeic acid , nitration , sodium borohydride , peroxynitrite , sodium nitrite , aqueous solution , radical , organic chemistry , reactivity (psychology) , photochemistry , antioxidant , catalysis , superoxide , medicine , enzyme , alternative medicine , pathology
The synthesis and spectroscopic properties of the three isomers of nitrocaffeic acid are described. The three p K a s of each isomer were measured by UV–visible spectroscopy. The comparison of the UV–visible spectra of nitrocaffeic acids and those obtained from the reaction of caffeic acid with reactive nitrogen species led to the conclusion that the nitration of caffeic acid with acidic nitrite does not significantly occur and confirmed the absence of nitration when caffeic acid reacts with peroxynitrite. Attempts to obtain free radical species from nitrocaffeic acids by classical methods showed a different reactivity to that of nitroaromatics and catechols. Nitrocaffeic acids do not autoxidize under aqueous basic conditions and are insensitive to t ‐BuOK or O 2 −· (two reactants known for their capabilities to oxidize catechols and reduce nitroaromatics). Nitroaromatic anion radicals may be obtained using sodium borohydride as reductant and are particularly stable under an uncontrolled atmosphere. Copyright © 2000 John Wiley & Sons, Ltd.